#
# GetoptLong for Ruby
#
# Copyright (C) 1998, 1999, 2000  Motoyuki Kasahara.
#
# You may redistribute and/or modify this library under the same license
# terms as Ruby.
#
# See GetoptLong for documentation.
#
# Additional documents and the latest version of `getoptlong.rb' can be
# found at http://www.sra.co.jp/people/m-kasahr/ruby/getoptlong/

# The GetoptLong class allows you to parse command line options similarly to
# the GNU getopt_long() C library call. Note, however, that GetoptLong is a
# pure Ruby implementation.
#
# GetoptLong allows for POSIX-style options like <tt>--file</tt> as well
# as single letter options like <tt>-f</tt>
#
# The empty option <tt>--</tt> (two minus symbols) is used to end option
# processing. This can be particularly important if options have optional
# arguments.
#
# Here is a simple example of usage:
#
#     require 'getoptlong'
#
#     opts = GetoptLong.new(
#       [ '--help', '-h', GetoptLong::NO_ARGUMENT ],
#       [ '--repeat', '-n', GetoptLong::REQUIRED_ARGUMENT ],
#       [ '--name', GetoptLong::OPTIONAL_ARGUMENT ]
#     )
#
#     dir = nil
#     name = nil
#     repetitions = 1
#     opts.each do |opt, arg|
#       case opt
#         when '--help'
#           puts <<-EOF
#     hello [OPTION] ... DIR
#
#     -h, --help:
#        show help
#
#     --repeat x, -n x:
#        repeat x times
#
#     --name [name]:
#        greet user by name, if name not supplied default is John
#
#     DIR: The directory in which to issue the greeting.
#           EOF
#         when '--repeat'
#           repetitions = arg.to_i
#         when '--name'
#           if arg == ''
#             name = 'John'
#           else
#             name = arg
#           end
#       end
#     end
#
#     if ARGV.length != 1
#       puts "Missing dir argument (try --help)"
#       exit 0
#     end
#
#     dir = ARGV.shift
#
#     Dir.chdir(dir)
#     for i in (1..repetitions)
#       print "Hello"
#       if name
#         print ", #{name}"
#       end
#       puts
#     end
#
# Example command line:
#
#     hello -n 6 --name -- /tmp
#
class GetoptLong
  #
  # Orderings.
  #
  ORDERINGS = [REQUIRE_ORDER = 0, PERMUTE = 1, RETURN_IN_ORDER = 2]

  #
  # Argument flags.
  #
  ARGUMENT_FLAGS = [NO_ARGUMENT = 0, REQUIRED_ARGUMENT = 1,
    OPTIONAL_ARGUMENT = 2]

  #
  # Status codes.
  #
  STATUS_YET, STATUS_STARTED, STATUS_TERMINATED = 0, 1, 2

  #
  # Error types.
  #
  class Error  < StandardError; end
  class AmbiguousOption   < Error; end
  class NeedlessArgument < Error; end
  class MissingArgument  < Error; end
  class InvalidOption    < Error; end

  #
  # Set up option processing.
  #
  # The options to support are passed to new() as an array of arrays.
  # Each sub-array contains any number of String option names which carry
  # the same meaning, and one of the following flags:
  #
  # GetoptLong::NO_ARGUMENT :: Option does not take an argument.
  #
  # GetoptLong::REQUIRED_ARGUMENT :: Option always takes an argument.
  #
  # GetoptLong::OPTIONAL_ARGUMENT :: Option may or may not take an argument.
  #
  # The first option name is considered to be the preferred (canonical) name.
  # Other than that, the elements of each sub-array can be in any order.
  #
  def initialize(*arguments)
    #
    # Current ordering.
    #
    if ENV.include?('POSIXLY_CORRECT')
      @ordering = REQUIRE_ORDER
    else
      @ordering = PERMUTE
    end

    #
    # Hash table of option names.
    # Keys of the table are option names, and their values are canonical
    # names of the options.
    #
    @canonical_names = Hash.new

    #
    # Hash table of argument flags.
    # Keys of the table are option names, and their values are argument
    # flags of the options.
    #
    @argument_flags = Hash.new

    #
    # Whether error messages are output to $stderr.
    #
    @quiet = FALSE

    #
    # Status code.
    #
    @status = STATUS_YET

    #
    # Error code.
    #
    @error = nil

    #
    # Error message.
    #
    @error_message = nil

    #
    # Rest of catenated short options.
    #
    @rest_singles = ''

    #
    # List of non-option-arguments.
    # Append them to ARGV when option processing is terminated.
    #
    @non_option_arguments = Array.new

    if 0 < arguments.length
      set_options(*arguments)
    end
  end

  #
  # Set the handling of the ordering of options and arguments.
  # A RuntimeError is raised if option processing has already started.
  #
  # The supplied value must be a member of GetoptLong::ORDERINGS. It alters
  # the processing of options as follows:
  #
  # <b>REQUIRE_ORDER</b> :
  #
  # Options are required to occur before non-options.
  #
  # Processing of options ends as soon as a word is encountered that has not
  # been preceded by an appropriate option flag.
  #
  # For example, if -a and -b are options which do not take arguments,
  # parsing command line arguments of '-a one -b two' would result in
  # 'one', '-b', 'two' being left in ARGV, and only ('-a', '') being
  # processed as an option/arg pair.
  #
  # This is the default ordering, if the environment variable
  # POSIXLY_CORRECT is set. (This is for compatibility with GNU getopt_long.)
  #
  # <b>PERMUTE</b> :
  #
  # Options can occur anywhere in the command line parsed. This is the
  # default behavior.
  #
  # Every sequence of words which can be interpreted as an option (with or
  # without argument) is treated as an option; non-option words are skipped.
  #
  # For example, if -a does not require an argument and -b optionally takes
  # an argument, parsing '-a one -b two three' would result in ('-a','') and
  # ('-b', 'two') being processed as option/arg pairs, and 'one','three'
  # being left in ARGV.
  #
  # If the ordering is set to PERMUTE but the environment variable
  # POSIXLY_CORRECT is set, REQUIRE_ORDER is used instead. This is for
  # compatibility with GNU getopt_long.
  #
  # <b>RETURN_IN_ORDER</b> :
  #
  # All words on the command line are processed as options. Words not
  # preceded by a short or long option flag are passed as arguments
  # with an option of '' (empty string).
  #
  # For example, if -a requires an argument but -b does not, a command line
  # of '-a one -b two three' would result in option/arg pairs of ('-a', 'one')
  # ('-b', ''), ('', 'two'), ('', 'three') being processed.
  #
  def ordering=(ordering)
    #
    # The method is failed if option processing has already started.
    #
    if @status != STATUS_YET
      set_error(ArgumentError, "argument error")
      raise RuntimeError,
        "invoke ordering=, but option processing has already started"
    end

    #
    # Check ordering.
    #
    if !ORDERINGS.include?(ordering)
      raise ArgumentError, "invalid ordering `#{ordering}'"
    end
    if ordering == PERMUTE && ENV.include?('POSIXLY_CORRECT')
      @ordering = REQUIRE_ORDER
    else
      @ordering = ordering
    end
  end

  #
  # Return ordering.
  #
  attr_reader :ordering

  #
  # Set options. Takes the same argument as GetoptLong.new.
  #
  # Raises a RuntimeError if option processing has already started.
  #
  def set_options(*arguments)
    #
    # The method is failed if option processing has already started.
    #
    if @status != STATUS_YET
      raise RuntimeError,
        "invoke set_options, but option processing has already started"
    end

    #
    # Clear tables of option names and argument flags.
    #
    @canonical_names.clear
    @argument_flags.clear

    arguments.each do |arg|
      if !arg.is_a?(Array)
       raise ArgumentError, "the option list contains non-Array argument"
      end

      #
      # Find an argument flag and it set to `argument_flag'.
      #
      argument_flag = nil
      arg.each do |i|
        if ARGUMENT_FLAGS.include?(i)
          if argument_flag != nil
            raise ArgumentError, "too many argument-flags"
          end
          argument_flag = i
        end
      end

      raise ArgumentError, "no argument-flag" if argument_flag == nil

      canonical_name = nil
      arg.each do |i|
        #
        # Check an option name.
        #
        next if i == argument_flag
        begin
          if !i.is_a?(String) || i !~ /^-([^-]|-.+)$/
            raise ArgumentError, "an invalid option `#{i}'"
          end
          if (@canonical_names.include?(i))
            raise ArgumentError, "option redefined `#{i}'"
          end
        rescue
          @canonical_names.clear
          @argument_flags.clear
          raise
        end

        #
        # Register the option (`i') to the `@canonical_names' and
        # `@canonical_names' Hashes.
        #
        if canonical_name == nil
          canonical_name = i
        end
        @canonical_names[i] = canonical_name
        @argument_flags[i] = argument_flag
      end
      raise ArgumentError, "no option name" if canonical_name == nil
    end
    return self
  end

  #
  # Set/Unset `quiet' mode.
  #
  attr_writer :quiet

  #
  # Return the flag of `quiet' mode.